tbuckley/cabot-search huggingface dataset:
Abstract 15402: P90 Ribosomal S6 Kinase Rescues Contractility of Myosin Light Chain Kinase Null Smooth Muscle
Authors: Jaspreet Kalra, Ramon J Ayon, Zaneta Markowska, Urszula Derewenda, Swapnil K Sonkusare, Avril V Somlyo
Journal: Circulation (2022)

Introduction: Smooth muscle (SM) contraction is regulated by an increase in [Ca 2+ ] , activation of myosin light chain kinase (MLCK) and phosphorylation of myosin regulatory light chain (RLC 20 ) activating myosin crossbridge cycling. MLCK null mice die at birth, but SM retains the ability to contract suggesting the presence of another kinase(s). Based on studies with WT and p90 ribosomal S-6 kinase (RSK2) null mice, we reported that RSK2 activity accounts for ~ 25% of maximal contractile force in wild type (WT) resistance arteries. Hypothesis: RSK2 confers contractility via RLC 20 activation in smooth muscle cells of MLCK null mice. Methods: Tension was measured on E18 aorta, bladder, and umbilical artery from WT and MLCK -/- embryos, in response to phenylephrine, carbachol, high potassium, SM myosin phosphatase, calyculinA (10 uM), as well as Ca 2+ following permeabilization with α-toxin. VSMCs were cultured from E18 MLCK -/- aortae and from WT and RSK2 -/- mouse mesenteric arteries. Serum starved cells were stimulated with serum and LPA (0.5 uM), in the presence and absence of RSK2 inhibitor, LJH685 (10 μM). Protein-protein interactions were assessed by in-situ PLA assay and immunoprecipitation. On-going in-vitro studies using purified myosin and kinases address RSK2 direct regulation of MLCK activity. Results: Strips from bladder SM and umbilical artery from WT and MLCK -/- embryos (E18), contracted in response to agonists and high [K]. pCa-tension curves showed the same sensitivity to Ca 2+ in MLCK -/- and WT. Maximal force induced by calyculinA was also the same indicating an intact normal contractile apparatus in the MLCK -/- . Significant phosphorylation of RLC 20 at Ser19 occurred in LPA- and serum-stimulated MLCK -/- SM cells, which was significantly inhibited by the RSK2 inhibitor, LJH685 (n=3). PLA assay showed co-localization of RSK2 and MLCK (&lt;40nm) (n=3). RSK2 is immunoprecipitated along with its activators ERK1/2, PDK1, suggestive of cross talk between RSK2 and MLCK on the actin filament (n=5). Conclusions: RSK2 signaling accounts for the contractile activity in the absence of MLCK. Furthermore, RSK2 and MLCK form a signaling complex on the actin filament, optimally positioning them for interaction with adjacent myosin heads.
Abstract 15328: Investigating the Role of Endothelial Breast Cancer Susceptibility Gene 2 in Doxorubicin-Induced Cardiotoxicity
Authors: Berk Rasheed, David Michels, Sepideh Nikfarjam, Shuhan Bu, Hien Chi Nguyen, Jefferson C Frisbee, David A Hess, Robert Gros, Krishna K Singh
Journal: Circulation (2022)

Background: Doxorubicin (DOX) is a chemotherapeutic drug used to treat various malignancies including breast cancer. However, DOX use is limited by DOX-induced cardiotoxicity (DIC), which carries a poor prognosis and is frequently fatal. Accumulating evidence indicates a central role of oxidative stress, DNA damage, inducing cellular inflammation and apoptosis as common pathways during DIC. BRCA2 functions to maintain genome-wide stability by promoting DNA damage repair and also has anti-oxidative and anti-inflammatory roles. Thus, the pathways of DIC; DNA damage, oxidative stress, inflammation and endotheliotoxiciy; are specifically regulated by BRCA2. However, the role of endothelial BRCA2 in the mechanisms driving DIC remain unknown. Hypothesis: We hypothesize that endothelial cell-specific loss-of BRCA2 exacerbates and prevents DOX- induced DNA damage, inflammation, endotheliotoxicity, and cardiomyocyte death promoting DIC. Methods and Results: To understand the effect of DOX on BRCA2 expression in vitro , we cultured Human Umbilical Vein Endothelial Cells (HUVECs) and performed time and dose experiments and extracted RNA and protein to perform qPCR and immunoblot, respectively, for BRCA2. DOX inhibited BRCA2 expression in HUVECs at transcript and protein levels. We also measured the expression of pro-apoptotic p53, which appear to be up-regulated by DOX in a dose/time-dependent manner. We also have generated and characterized endothelial cell-specific BRCA2 knockout mice (BRCA2 endo ) using the Cre-Lox P method. DOX treatment to BRCA2 endo mice induced significant weight loss in comparison to wild-type (WT) mice. Echocardiography done on DOX-treated BRCA2 endo and WT mice showed significantly reduced cardiac function in BRCA2 endo mice compared to WT mice. Our qPCR data performed on RNAs extracted from DOX-treated BRCA2 endo and WT mice demonstrated significantly increased expression of heart failure markers in the heart of BRCA2 endo mice compared to WT mice. Conclusion: Our studies’ will provide a novel mechanism for DIC by elucidating the roles of endotheliotoxicity and determining whether BRCA2’s function is a critical factor for restorative DNA damage repair and recovery of endothelial cell function following DOX treatment.
Abstract 15719: Proteomic Analyses Reveal Mechanistic Links Between Clonal Hematopoiesis of Indeterminate Potential and Coronary Artery Disease
Authors: Zhi Yu, Bing Yu, Amelie Vromman, Quynh H Nguyen, Sumeet Khetarpal, Michael Honigberg, Amy E Lin, Daniel H Katz, Usman A Tahir, Joshua S Weinstock, Siddhartha Jaiswal, Thomas Austin, Vasan S Ramachandran, Gina Peloso, Joann E Manson, Bernhard Haring, Charles Kooperberg, Alex P Reiner, Joshua Bis, Bruce M Psaty, Adolfo Correa, Leslie Lange, Wendy S Post, Jerome I Rotter, Stephen S Rich, James Wilson, Christie M Ballantyne, Josef Coresh, Vijay Sankaran, Peter Libby, Alexander G Bick, Benjamin L Ebert, Robert E Gerszten, Pradeep Natarajan
Journal: Circulation (2022)

Introduction: Clonal hematopoiesis of indeterminate potential (CHIP) is a phenomenon where hematopoietic stem cells acquire leukemogenic mutations without blood cancer. CHIP is a causal risk factor for coronary artery disease (CAD), yet underlying mechanisms remain unclear. The plasma proteome may provide novel mechanistic insights into the links between CHIP and CAD. Methods: We studied the associations of CHIP with the plasma proteins and CAD risk in four Trans-Omics for Precision Medicine (TOPMed) longitudinal cohorts: ARIC (N=9,084), CHS (N=1,727), JHS (N=1,858), and MESA (N=978). CHIP (variant allele fraction &gt;2%) was identified from whole genome sequences of blood DNA and modeled both as a composite of the most common drivers ( DNMT3A , TET2 , ASXL1 , and JAK2 ) and separately. Levels of ~1,300 serum proteins measured by SomaScan were log-transformed and residualized on study-specific covariates. The association between CHIP and protein levels was estimated across all participants within each study, as well as by sex, and meta-analyzed. For proteins significantly (FDR&lt;0.05) associated with CHIP, pathway analysis and functional validation in Tet2-/- mice were conducted. Results: Across all studies (mean age: 59.8 y; 43.6% male), 720 (5.6%) individuals were identified with CHIP. There were 143 significant CHIP-protein pairs, with carbonic anhydrase 1, lysozyme C, and properdin being the most associated proteins. TET2 had the largest number of, and strongest, associations among examined driver genes. In sex-stratified analysis, follicle-stimulating hormone was inversely associated in females. Pathway analysis implicated the inflammation-related STAT3 and IL-17 signaling pathways. We observed significantly greater expression of Cfp and Lyz (encoding properdin and lysosome C, respectively) in the monocytes of Tet2 -/- female mice compared to wild-type female mice and Tet2 -/- male mice. A number of proteins (including PCSK9) were significantly associated with both CHIP and CAD, suggesting both shared and nonshared mechanisms. Conclusions: CHIP, particularly TET2 , is broadly associated with plasma proteins, as validated by evidence in Tet2-/- mice. Further studies are needed to understand the biological mechanisms linking CHIP to CAD.
Abstract 15302: Successful Transesophageal Echocardiograms in Two Patients With Esophagectomy
Authors: Michael Silverman, Perry Wengrofsky, Ravi Chokshi, Alfonso H Waller
Journal: Circulation (2022)

Clinical Presentation: Case 1: A 74-year-old man was admitted to the ICU with altered mental status and shortness of breath. The patient had a history of esophageal adenocarcinoma and underwent an Ivor-Lewis esophagectomy 5 months prior. Blood cultures grew candida glabrata and the patient was started on an antifungal medication. A transthoracic echocardiogram was done without evidence of infective endocarditis. A transesophageal echocardiogram (TEE) was requested for higher quality imaging of the valves. Case 2: A 57-year-old man with a history of esophageal cancer with an esophagectomy done 4 years prior and atrial fibrillation (AF) presented for recurrence of AF. The patient had been maintained on apixaban and metoprolol but developed melena as well as reoccurrence of AF. An AF ablation was performed and a left atrial ablation appendage closure with a WATCHMAN device was planned for 6 weeks later. A TEE was requested intraoperatively for device guidance. Imaging Findings: In both cases, CT scans of the chest and abdomen within the last 4 months were reviewed to ensure patency of the esophagogastric anastomosis. In case 1, the TEE was performed with our standard scope without complication and showed no gross vegetations or abnormalities. In case 2, the TEE was performed with our standard scope without difficulty and showed a 20 mm x 21 mm x 20 mm left atrial appendage without thrombus. The WATCHMAN device was deployed successfully. Summary and Discussion Points: In our two patient cases, we were able to successfully perform TEE without complication in the setting of prior esophagectomy. Prior esophagectomy has traditionally been considered a barrier for TEE which can lead to limited evaluation and treatment of patients with esophagectomies where a TEE is required. In our cases, we consulted the patients’ surgeons who performed the esophagectomies and analyzed the CT images prior to performing the procedures to ensure the safety and feasibility of performing the TEE.
Abstract 15463: Association of Coronary Plaque Morphology With Inflammatory Biomarkers and Target Lesion Revascularization in Patients With Stable Angina Pectoris
Authors: Kohei Saiin, Takao Konishi, Sho Kazui, Yutaro Yasui, Yuki Takahashi, Seiichiro Naito, Sakae Takenaka, Yoshifumi Mizuguchi, Atsushi Tada, Yuta Kobayashi, Yoshiya Kato, Kazunori Omote, Takuma Sato, Kiwamu Kamiya, Toshiyuki Nagai, Shinya Tanaka, Toshihisa Anzai
Journal: Circulation (2022)

Background: In many countries, coronary artery disease (CAD) is one of the most common causes of death, and stable angina pectoris (SAP) is the most common initial symptomatic presentation. Despite the contemporary evolution of percutaneous coronary intervention (PCI) using drug-eluting stenting and a drug-coated balloon, restenosis and repeat revascularization still remain major concerns and are limiting the efficacy of PCI in patients with SAP . The characteristics of high-risk coronary atherosclerosis evaluated by optical coherence tomography (OCT) were suggested to have a prognostic role. Inflammatory biomarkers may be related to coronary artery disease severity. Accordingly, this study aimed to investigate the association of high-risk coronary plaque morphologies detected by OCT with circulating inflammatory biomarkers and adverse cardiovascular events. Methods: We prospectively analyzed the data of 30 consecutive patients with stable angina pectoris (SAP) who underwent percutaneous coronary intervention (PCI) using optical coherence tomography (OCT) between April 2020 and November 2020 in our university hospital. Inflammatory biomarker measurement and an OCT analysis focused on high-risk coronary plaque features were performed. Based on the coronary plaque risk score (CPRS), patients were defined as having a low CPRS (CPRS ≤3) or high CPRS (CPRS ≥4). The primary outcome was target lesion revascularization (TLR). Results: TLR occurred in 6 patients (20%) within 15 months after PCI. A high CPRS assessed by OCT was directly correlated to TLR (P=0.029). In a logistic regression analysis, the CPRS was associated with TLR (odds ratio, 10.0; 95% confidence interval, 1.34-74.5). Among inflammatory biomarkers, MCP-1 was significantly correlated with the CPRS (P=0.020). Conclusions: In patients with SAP, the CPRS may be a potential surrogate index for predicting TLR. MCP-1 might be useful for detecting high-risk coronary atherosclerosis.
Abstract 15299: Association Between Change in Liver Stiffness and Adverse Outcomes in Individuals With Fontan Circulation
Authors: Samuel W Brayer, Joseph J Palermo, Khurram Bari, Alexander R Opotowsky, Cara E Morin, Andrew T Trout, Jonathan R Dillman, Adam M Lubert
Journal: Circulation (2022)

Introduction: Fontan-associated liver disease (FALD) contributes to adverse outcomes late after the Fontan procedure. Elevated Magnetic Resonance Elastography-derived Liver Stiffness (MRE-LS) is associated with higher Fontan pressure and Fontan circulatory failure (FCF). How MRE-LS changes over time and if it can predict adverse outcomes has not been studied. Methods: Single center retrospective study of individuals &gt;10 years-old post-Fontan with &gt;1 MRE-LS study between 2010-2020. Absolute change in liver stiffness (shear modulus in kilopascals, kPa) was defined as the difference between first and second MRE-LS measures. Demographic and clinical data were collected. FCF was defined as the composite outcome of death, transplant, VAD placement, or unscheduled cardiac hospitalization following index MRE. To compare the effect of magnitude of change in liver stiffness, patients were ordered from lowest negative to highest positive (Quartile 1-4) change. Results: 77 individuals were included (mean age at first MRI 19.9±6.7 years, 47% female). Baseline MRE-LS was 4.4±1.0 kPa, follow-up MRE-LS was 4.1±1.1 kPa with mean time between MRE examinations of 46±27 months. The median annual change in MRE-LS was -0.06 (IQR -0.2-0.05) kPa/year. There was no association between change in MRE-LS and age ventricular dysfunction, or Fontan pressure. FCF occurred in 18 (23%) individuals, and those with FCF had a greater increase in MRE-LS (0.12±0.83 vs -0.42±0.96 kPa, p=0.04, Figure). Conclusions: MRE-LS remains stable over short-term follow-up in most individuals with Fontan circulation. However, those with greater positive change in liver stiffness were more likely to experience adverse outcomes. An increase in MRE-LS is a potential non-invasive biomarker of clinical decompensation. Figure: Probability of endpoint-free survival based on the change in liver stiffness quartiles (4 = largest increase in MRE-LS). Tick marks on curves indicate patients censored.
Abstract 15322: O-glcnac Modification on Runx2 Promotes Vascular Calcification
Authors: Chang Hyun Byon, Yong Sun, Jack Heath, Xia Mao, Xinyang Zhao, Hui Wu, Yabing Chen
Journal: Circulation (2022)

Vascular calcification is prevalent in patients with diabetes mellitus and well documented in animal models of diabetes. We have previously reported that vascular calcification in diabetes is associated with elevated vascular protein O -linked GlcNAc modification ( O -GlcNAcylation). The present studies sought to determine a causative link of O -GlcNAcylation with diabetic vascular calcification and the underlying molecular mechanisms. Using coronary arteries from diabetic subjects, we identified increased O -GlcNAcylation in the highly calcified lesions compared to those in the surrounding uncalcified areas. By generating a new mouse model with inducible SMC-specific deletion of the O -GlcNAc transferase (OGT), we demonstrated that smooth muscle cell (SMC)-specific OGT deletion significantly inhibited protein O -GlcNAcylation and calcification, and decreased aortic stiffness in the low-dose streptozotocin-induced diabetic mice. Consistent with the observations in human tissues, inhibition of vascular calcification by OGT ablation was associated with down-regulation of Runx2, the essential osteogenic regulator for vascular calcification. OGT deficiency in VSMC further attenuated Runx2-induced VSMC calcification. Immunoprecipitation analysis uncovered a direct O-GlcNAc modification on Runx2, which was abolished in the OGT-deficient VSMC. With a serial of Runx2 truncation mutants and point mutations on putative O -GlcNAcylation sites, we localized the essential Runx2 osteogenic functional domain between amino acids 391 and 432, and identified Runx2 T412 was responsible for Runx2 O -GlcNAcylation and Runx2-induced VSMC calcification. Inhibition of Runx2 O -GlcNAcylation by T412A mutation decreased Runx2 transcription activity and inhibited Runx2 binding with its key co-factors. Taken together, our studies have provided the first genetic proof demonstrating the causative effects of O -GlcNAcylation on vascular calcification in diabetes, and identified a novel mechanism underlying the essential role of O -GlcNAcylation of Runx2 in Runx2 osteogenic activity and Runx2-induced VSMC calcification. These results may shed lights on novel targets that are amenable to drug discovery for diabetic vascular calcification.
Abstract 15432: Post-Operative Systolic Dysfunction Following Aortic Root Replacement Surgery in Patients With Marfan Syndrome
Authors: Brynn S Connor, Claudia Algaze, D C Miller, David Liang, Ronnie T Collins
Journal: Circulation (2022)

Introduction: Cardiovascular disease is the leading cause of morbidity and premature mortality in Marfan Syndrome (MFS), with ≥ 50% of patients requiring prophylactic aortic root surgery for management of progressive aortic dilation. Given evidence for intrinsic myocardial dysfunction in MFS, patients may be at an increased risk of developing post-operative dysfunction and related cardiovascular complications following cardiac surgery. Our aim was to determine the prevalence, persistence, and long-term outcomes of post-operative ventricular dysfunction in MFS following aortic root replacement surgery. Methods: All adult patients with a confirmed diagnosis of MFS who underwent aortic root replacement surgery at Stanford from January 1995 to December 2021 were included. Post-operative systolic dysfunction was defined as a left ventricular ejection fraction (LVEF) &lt;55% on transthoracic echocardiography at hospital discharge. Potential genetic, operative, and cardiac risk modifiers were also recorded. Results: There were 274 patients with MFS (64% male, 71% White) who underwent aortic root replacement surgery, followed over a median duration of 11 years (IQR 5, 16). Post-operative systolic dysfunction was present in 93 patients (33.9%), with a median LVEF of 46.9% (IQR 42.0, 50.5), median decrement in LVEF of 10.9% (IQR 5.5, 19.0), and median duration of persistence of 22 months (IQR 8.0, 57.3). There was no significant association with traditional operative nor cardiovascular risk variables. Patients with a reduced pre-operative LVEF were three times more likely to have worsened post-operative systolic function (OR=3.6, 95% CI=1.2-10.8, p=0.02), demonstrated more severe systolic impairment (LVEF &lt;30%: OR 1.8, 95% CI=1.4-26.1, p=0.02), and exhibited persistent dysfunction (≥5 years: OR 1.6, 95% CI=1.8-14.6, p=0.002). Conclusions: Post-operative systolic dysfunction is common in patients with MFS following aortic root replacement surgery. A reduced pre-operative LVEF is associated with more severe and protracted post-operative impairment, and therefore may be an important consideration for surgical timing.
Abstract 15294: Right Atrial Thrombus Extraction Through Angiovac - A Challenge Based on Chronicity
Authors: Murrium I Sadaf, Tushar Tarun
Journal: Circulation (2022)

Case Presentation: 23-year-old woman with right ovarian dysgerminoma, treated with debulking surgery and bleomycin, etoposide, and platinum, found to have a right atrial (RA) mass on post-chemotherapy surveillance CT and referred to the cardiology clinic. Her vitals were stable, lungs were clear to auscultation, RRR without murmurs, no JVD or LE edema. On labs, hgb:11g/dL and LDH:283 units/L(135 to 214 units/L). A transthoracic echocardiogram (TTE) and a cardiac MRI revealed a mass of RA at the junction of inferior vena cava (IVC) entry into RA, measuring 3x1.3 cm in the 2-chamber view and 2.4x1.8 cm in the 4-chamber view (Fig A,B) with prolapse into the right ventricle (RV) in diastole. Based on cardiac MRI’s short and long inversion time imaging characteristics, thrombus was the most likely diagnosis (Fig C). Shared decision-making with the patient included options: 1) open heart surgery for removal; 2) interventional aspiration thrombectomy; or 3) conservative treatment with anticoagulation (AC). After six weeks of AC with enoxaparin, TTE revealed a RA thrombus of the same size as previously (2.8x1.2 cm). Given the lack of improvement, she agreed to an invasive procedure to remove the mass using an AngioVac aspiration system (AngioDynamics, Latham, NY). The AngioVac cannula maneuvered in the RA under fluoroscopic and TEE guidance to capture the RA mass. However, the mass broke into two pieces, one piece still attached to the RA and the other piece lodged in the AngioVac cannula (Fig D,E). She remained hemodynamically stable after the procedure. The pathology of the RA mass revealed an organized thrombus (Fig F). She had no complaints on follow-up in the clinic and continued on AC for 6 months. Discussion: Percutaneous aspiration thrombectomy using the AngioVac system has become a novel option for removing commonly encountered intravascular material, such as fresh thrombi or emboli in the RA, RV, SVA, IVC, and the iliofemoral vein, but may be complicated in old thrombi.
Abstract 15277: High-Throughput Optical Oxygen Measurements for Human IPSC-Cardiomyocytes and Ventricular Fibroblasts in 96-Well Plates
Authors: Weizhen Li, David McLeod, John Ketzenberger, Matthew W Kay, Zhenyu Li, Emilia Entcheva
Journal: Circulation (2022)

For metabolically active cells like ﻿cardiomyocytes, a balanced state of oxygen supply and demand is crucial for basic cell function. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a valuable experimental model due of their scalability and relevance to human physiology. Oxygen consumption and availability have not been characterized in high-throughput format (HT), used in pre-clinical studies. Here, we quantified pericellular oxygen in syncytia of hiPSC-CM and human cardiac fibroblasts, grown in glass-bottom 96-well plates ( Fig 1A-C ). We deployed Ruthenium-based oxygen sensors and a ratiometric optical oxygen measurement system ( Fig 1B ) to track pericellular oxygen over time across all wells. Measured ratios were calibrated to % oxygen using two-point calibration with 5% Na 2 SO 3 and upon saturation with ambient air. Solution height and cell density were varied (4 solution heights, 3 cell densities) to understand their role in oxygen diffusion and oxygen consumption rate (OCR) by the cells. ﻿Michaelis-Menten kinetics and the Thiele modulus were used to computationally simulate oxygen availability in matching conditions. Without active perfusion or mass transport, for all tested conditions in the hiPSC-CMs, oxygen was depleted to &lt;5% within approximately an hour. The drop of oxygen occurred in two phases - a zero-order decrease phase, followed by ﻿Michaelis-Menten kinetic phase ( Fig 1D ). Increase in culture medium volume/ height was found to be a powerful determinate of oxygen availability in simulations and in experiments ( Fig 1E n = 5 per group). Higher cell density correlated with steeper slope in the first phase of decline in oxygen availability, n = 4 per group. Cardiac fibroblasts followed a similar pattern (n = 4 per group) with noticeably slower OCR. Overall, our results indicate that pericellular oxygen in HT glass-bottom plates may reach hypoxic levels quickly; solutions for active mass transport need to be considered.